For converting page I use this fre software (GPL3) https://github.com/wkhtmltopdf/wkhtmltopdf
I'm looking for a tool that convert pages by using the CSS (of the page). (like this pdf Philosophy of the GNU Project.pdf. I get this by printing from firefox (print to file option)) but with wkhtmltopdf I get this pdf (Philosophy_of_the_GNU_Project_-_GNU_Project_-_Free_Software_Foundation.en_.pdf).
